Lemma 5.2 ([1]}) 
Let \((T_j)_{j\ge 0}\)  be a sequence in \({L}_2\)  such that \(\sum \Vert T_j\Vert _{{L}_2}^2 < \infty \) . Assume further that the sequence \((T_j)_{j\ge 0}\)  is left-disjoint or right-disjoint. Then, we have
\(\mu ^2\bigg (\bigoplus _{j\ge 0} T_j\bigg )\prec \mu ^2\bigg (\sum _{j\ge 0} T_j\bigg ).\) 

